System and/or method for monitoring and/or controlling the relative internal air pressure of a facility

ABSTRACT

A system is provided for maintaining a balanced interior air pressure in a building ( 10 ) having a plurality of different localized areas ( 20 ). The system includes: a main fan or set of main fans ( 12 ) that is selectively controlled to support a desired overall interior air pressure inside the building ( 10 ); a plurality of interior sensors ( 22 ), each interior sensor ( 22 ) arranged to detect a localized air pressure at one of the areas ( 20 ) in the building; a plurality of auxiliary fans ( 26 ), each auxiliary fan ( 26 ) being provisioned to selectively modify the localized air pressure at one of the areas ( 20 ) in the building ( 10 ); and, a control unit ( 11 ) that is in operative communication with the plurality of sensors ( 22 ) to obtain air pressure readings therefrom, in operative communication with the plurality of auxiliary fans ( 26 ) to control operation thereof, and in operative communication with the main fan or set of main fans ( 12 ) to control operation thereof. Suitably, based upon the localized air pressure detected by a given sensor ( 22 ), a corresponding auxiliary fan ( 26 ), provisioned for the area in which the air pressure was detected by the given sensor ( 22 ), is controlled by the control unit ( 11 ) to modify the localized air pressure at the area ( 20 ) in the building ( 10 ) for which the corresponding auxiliary fan ( 26 ) was provisioned.

FIELD

The present inventive subject matter relates to the art of air pressuremonitoring and/or control within a facility. Particular application isfound in conjunction with certain types of positively pressurizedfacilities or buildings, and the specification makes particularreference thereto. However, it is to be appreciated that aspects of thepresent inventive subject matter are also amenable to other likeapplications.

BACKGROUND

Commonly, it is desired in some buildings and other facilities to havean internal positive air pressure relative to the outside ambient airpressure. For example, a relative positive internal air pressure isoften maintained in facilities where it is desired to keep exteriorairborne or other contaminates (e.g., dust, hazardous material, fumes,etc.) from entering the building. For example, relative positiveinternal air pressure is often employed in hospitals or other medicalfacilities, computer rooms, telecommunication offices, delicatemanufacturing plants, etc. As can be appreciated, the relativelypositive internal air pressure generally promotes airflow throughopenings in the facility or building in an interior to exteriordirection, thereby minimizing or otherwise inhibiting airborne or otherlike contaminates from entering the facility or building through thoseopenings. Typically, a building may employ an HVAC (Heating, Ventilationand Air Conditioning) system to achieve the relative positive internalair pressure. For example, the HVAC system may include an air intakevent and/or fan or the like that draws or otherwise forces exterior airinto the building (e.g., through a suitable filter) to achieve thedesired positive air pressure within the building relative to theoutside air pressure.

While normally a relative positive internal air pressure may begenerally maintained in a building or facility, there can be at timeslocalized interior air pressure variations in and/or about the faculty,e.g., caused by localized variations in the outside air pressure,openings in the building, etc. Accordingly, while an overall positiveinterior air pressure may be maintained in the facility or buildingrelative to the outside air pressure, the relative interior air pressuremay tend to become negative (or not sufficiently positive) at somelocalized points or areas in the facility or building due to theaforementioned causes and/or other reasons. Having such localized pointsor areas of weak or negative air pressure within a building or facilityrelative to the exterior air pressure is generally undesirable in manycases, e.g., insomuch as it may facilitate (or in any event notsufficiently hinder) airborne and/or other like contaminants fromentering the building at those localized points or areas. While this maynot always be a significant problem, it may become so after a wildfire,chemical spill, dirty bomb, or other abnormal event that contaminatesthe outside air or otherwise significantly degrades the exterior airquality.

Generally, the aforementioned localized variants (i.e., localized areaswithin the building tending or prone to have a weak or negative internalair pressure relative to the exterior air pressure) are addressed bysimply over-engineering the HVAC system or other positive pressureproducing system, i.e., so that the overall relative positive internalair pressure generated within the build or facility significantlyexceeds the expected demand or what would otherwise be normally desired.However, such a solution has certain limitations and/or drawbacks. Forexample, the “over-engineering” solution generally wastes energy in thecreation of the excess air pressure. Additionally, added cooling and/orheating expenses associated with conditioning the excess air flowingthrough the facility can also undesirably accompany this solution.Furthermore, the extra air movement itself can be a negativeconsequence.

Yet another drawback to the over-engineering solution is the potentialto actually increase contamination of the interior air. For example,such over-engineering generally means that more outside air must bebrought into the facility and that can in turn increase the overallinterior contamination since any implemented filtering may not remove100% of the contaminates. Finally, moving additional air through filterswill tend to cause the filters to become clogged more quickly. This canbe especially true when the exterior air contamination is significantlyhigh, which is also precisely when a relatively positive interior airpressure is most desirable.

Accordingly, a new and improved internal air pressure monitoring and/orcontrol system and/or method is disclosed that addresses theabove-referenced problems and others.

SUMMARY

In accordance with one embodiment, a system is provided for maintaininga balanced interior air pressure in a building having a plurality ofdifferent localized areas. The system includes: a main fan or set ofmain fans that is selectively controlled to support a desired overallinterior air pressure inside the building; a plurality of interiorsensors, each interior sensor arranged to detect a localized airpressure at one of the areas in the building; a plurality of auxiliaryfans, each auxiliary fan being provisioned to selectively modify thelocalized air pressure at one of the areas in the building; and, acontrol unit that is in operative communication with the plurality ofsensors to obtain air pressure readings therefrom, in operativecommunication with the plurality of auxiliary fans to control operationthereof, and in operative communication with the main fan or set of mainfans to control operation thereof. Suitably, based upon the localizedair pressure detected by a given sensor, a corresponding auxiliary fan,provisioned for the area in which the air pressure was detected by thegiven sensor, is controlled by the control unit to modify the localizedair pressure at the area in the building for which the correspondingauxiliary fan was provisioned.

In accordance with another embodiment, a method is provided formaintaining a balanced interior air pressure in a building having aplurality of different localized areas. The method includes: selectivelycontrolling a flow of exterior air into the building to support adesired overall interior air pressure inside the building; detecting alocalized interior air pressure in each of the localized areas in thebuilding; and, selectively modifying the localized interior air pressurein a given localized area of the building in response to the detectedlocalized interior air pressure at the given localized area varying fromthe desired overall interior air pressure.

Numerous advantages and benefits of the inventive subject matterdisclosed herein will become apparent to those of ordinary skill in theart upon reading and understanding the present specification.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive subject matter disclosed herein may take form in variouscomponents and arrangements of components, and in various steps andarrangements of steps. The drawings are only for purposes ofillustrating preferred embodiments and are not to be construed aslimiting. Further, it is to be appreciated that the drawings are not toscale.

FIG. 1 is diagrammatic illustration showing an exemplary internal airpressure control and/or regulation system suitable for practicingaspects of the present inventive subject matter.

FIG. 2 is a flow chart showing an exemplary process or method inaccordance with aspects of the present inventive subject matter forbalancing internal air pressure within a building and/or correctinglocalized variations in the internal air pressure.

FIG. 3 is a flow chart showing an exemplary process or method inaccordance with aspects of the present inventive subject matter fordiscriminating generalized changes in the overall interior air pressurefrom localized variations in the internal air pressure and suitablycorrecting for the former.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

For clarity and simplicity, the present specification shall refer tostructural and/or functional elements, entities and/or facilities,relevant standards, protocols and/or services, and other components thatare commonly known in the art without further detailed explanation as totheir configuration or operation except to the extent they have beenmodified or altered in accordance with and/or to accommodate thepreferred embodiment(s) presented herein.

With reference now to FIG. 1, there is shown a facility or building 10including an HVAC system regulated and/or otherwise controlled by an airpressure control unit (APCU) 11 to suitably maintain a balanced airpressure in the building 10 that is generally positive overall relativeto an air pressure outside the building 10. As shown, the HVAC systemincludes a main air intake fan or set of main air intake fans 12 that isselectively operated and/or controlled to draw or otherwise forceexterior air obtained via a vent 14 into the building 10, e.g., througha suitable air filter 16. Optionally, the filtered air is in turndelivered via ducts 18 into various rooms or localized areas 20 of thebuilding 10. For simplicity and clarity herein, FIG. 1 shows thebuilding 10 including only two rooms or localized areas 20. However, inpractice, the building 10 may optionally include any suitable number ofrooms or localized areas (i.e., more or less than two) arranged and/orequipped similarly to the exemplary rooms or areas 20 illustrated inFIG. 1.

Suitably, each room/area 20 is equipped or otherwise provisioned with asensor 22 that measures or otherwise detects the localized internal airpressure in the room/area 20 where the sensor 22 is located. Suitably,the sensors 22 are wirelessly connected to the APCU 11, e.g., via aradio frequency (RF) or other suitable over-the-air interface.Alternately, the sensors 22 may optionally be hardwired to the APCU 11.In either case, the sensors 22 are arranged to report, send or otherwisecommunicate localized interior air pressure measurements or other likereadings to the APCU 11. Suitably, the sensors 22 may automatically sendthe measurements or readings periodically, or the sensors 22 may returnthe reported data, e.g., in response to polling or requests receivedfrom the APCU 11, or the data may be intermittently or otherwisecommunicated from the sensors 22 to the APCU 11 as desired.

Similarly, the outside or exterior ambient air pressure is optionallymeasured or otherwise detected by one or more corresponding sensors(e.g., such as the illustrated sensors 24) that are located or otherwisearranged about an exterior of the facility or building 10. Suitably, thesensors 24 are wirelessly connected to the APCU 11, e.g., via an RF orother suitable over-the-air interface. Alternately, the sensors 24 mayoptionally be hardwired to the APCU 11. In either case, the sensors 24are arranged to report, send or otherwise communicate exterior airpressure measurements or other like readings to the APCU 11. Suitably,the sensors 24 may automatically send the measurements or readingsperiodically, or the sensors 24 may return the reported data, e.g., inresponse to polling or requests received from the APCU 11, or the datamay be intermittently or otherwise communicated from the sensors 24 tothe APCU 11 as desired.

Under normal operating conditions, suitably the main fan or set of mainfans 12 is operated and/or controlled by the APCU 11 (e.g., byregulating its speed) to produce and/or maintain a sufficient airflow togenerate a generally positive overall air pressure inside the building10 relative to the air pressure outside the building 10, i.e., theambient and/or exterior air pressure which is, for example, made knownor available to the APCU 11 in accordance with air pressure measurementsand/or other like readings obtained by the exterior sensors 24.Optionally, the fan 12 is wirelessly operated and/or controlled by theAPCU 11, e.g., via an RF or other suitable over-the-air interfaceoperatively connecting the two for communication therebetween, oralternately, the fan 12 and APCU 11 may be operatively connected to oneanother via a hardwired communication link. In either event, inaccordance with one exemplary embodiment, the APCU 11 optionallycontrols the operation and/or speed of the fan 12 based upon knowledgeof the exterior air pressure obtained from the sensors 24, e.g., so asto produce a desired generally positive overall air pressure inside thebuilding 10 relative to the air pressure outside the building 10. Forexample, optionally, when a relatively lower exterior air pressure ismeasured or otherwise detected by the sensors 24, then the APCU 11 setsa relatively lower operational speed for the fan 12, and conversely,when a relatively higher exterior air pressure is measured or otherwisedetected by the sensors 24, then the APCU 11 sets a relatively higheroperational speed for the fan 12. In this manner, the airflow and/orpressure generated by the selective operation and/or control of the mainfan or set of main fans 12 generally results in an overall interior airpressure being produced and/or maintained that is positive by a desiredamount relative to the exterior air pressure.

Suitably, the APCU 11 is also programmed or otherwise provisioned toproduce and/or maintain a substantially balanced air pressure inside thebuilding 10, i.e., to eliminate or minimize localized variations in theinternal air pressure. Optionally, the APCU 11 achieves theaforementioned balancing by selectively operating and/or controlling oneor more auxiliary fans (e.g., such as the fans 26 illustrated in FIG. 1)that are located or otherwise arranged within the facility or building10, e.g., in or adjacent or otherwise near particular rooms or areas 20of the facility or building 10. Optionally, the fans 26 are wirelesslyoperated and/or controlled by the APCU 11, e.g., via an RF or othersuitable over-the-air interface operatively interconnecting the elementsfor communication therebetween, or alternately, the fans 26 and APCU 11may be operatively connected to one another via one or more hardwiredcommunication links.

Regardless of the implemented communication channel, by appropriatelyoperating and/or controlling a particular fan 26 provisioned for orotherwise corresponding to a particular localized area inside thebuilding 10 (e.g., such as a particular room or area 20) that has a weakor negative air pressure (e.g., relative to an air pressure outside thebuilding 10), the APCU 11 can suitably boost or otherwise augment oralter the localized air pressure in the particular localized area toeliminate or minimize the localized variation. For example, in oneexemplary embodiment, the APCU 11 compares localized interior airpressure measurements or other like readings obtained from the interiorsensors 22 to the air pressure measurement or other like readingobtained from the exterior sensors 24. Optionally, in anotheralternative embodiment, the APCU 11 simply compares the localizedinterior air pressure measurements or other like readings obtained fromthe interior sensors 22 to a set, defined or otherwise determinedthreshold (e.g., the generally positive overall interior air pressure atwhich one desires to maintain the building 10). In either case, if theinterior air pressure measured or detected in a given localized areawhere one of the interior sensors 22 is located (e.g., a particularroom/area 20) is not sufficiently positive relative to the exterior airpressure measured or detected by the corresponding exterior sensor 24,or as the case may be, if the particular localized interior air pressuredoes not suitably meet the determined threshold, then the APCU 11signals or otherwise switches on the particular fan 26 provisioned foror corresponding to that particular localized area (i.e., the particularroom/area 20) so as to suitably boost or otherwise augment or alter thelocalized air pressure in the particular localized area.

Suitably, having turned-on a particular auxiliary fan 26, depending onthe magnitude or size of the difference between the localized interiorair pressure measured or detected in the given localized area at issue(e.g., the air pressure in the corresponding room/area 20 measured bythe corresponding interior sensor 22) and the exterior air pressure(e.g., measured or detected by the corresponding exterior sensor 24), oras the case may be, depending on the magnitude or size of the differencebetween the localized internal air pressure and the determinedthreshold, the APCU 11 optionally controls the speed of the turned-onauxiliary fan 26 to produce and/or maintain an airflow therefrom thatresults in a sufficiently corrective boost, augmentation or othersuitable alteration of the localized internal air pressure so as to makethe localized internal air pressure positive by a desired amountrelative to the exterior air pressure or so as to otherwise make thelocalized internal air pressure meet the determined threshold.Optionally, once the localized interior air pressure has been restoredto a sufficiently positive level relative to the exterior air pressure(e.g., as measured or detected by the respective sensors 22 and 24), oras the case may be, once the localized interior air pressure has meetthe threshold, the operational speed of the corresponding auxiliary fan26 may be maintained by the APCU 11. However, if the localized interiorair pressure starts to rise or become overly positive relative to theexterior air pressure or threshold, e.g., due to the operation and/orspeed of the corresponding auxiliary fan 26, the APCU 11 may thenaccordingly reduce the operational speed of the auxiliary fan 26 or evenshut-off the fan 26 altogether in order to maintain the localizedinternal air pressure at the desired level relative to the exterior airpressure and/or threshold. Of course, if the localized internal airpressure again becomes too weak or negative (e.g., relative to theexterior air pressure or threshold), then the APCU 11 optionally turnsthe corresponding auxiliary fan 26 back on and/or increases itsoperational speed accordingly in order to maintain the localizedinternal air pressure at the desired level relative to the exterior airpressure and/or threshold. In this manner, by individually operatingand/or controlling separate auxiliary fans 26 located and/or otherwisearranged to provide localized airflow and/or localized air pressureadjustments to different localized areas in the building 10 (e.g., suchas the different rooms/areas 20 illustrated in FIG. 1) based uponspecific localized interior air pressure measurements and/or readingsfor the different localized areas in the building 10 (e.g., obtained bythe interior air pressure sensors 22), the APCU 11 is able to produceand/or maintain a substantially balanced air pressure inside thebuilding 10 which is sufficiently positive by a desired amount orthreshold, e.g., relative to the air pressure outside the building 10(e.g., measured or detected by the exterior air pressure sensors 24).

Suitably, the APCU 11 continually or otherwise monitors and/or recordsthe states of each auxiliary fan 26 arranged within the facility orbuilding 10, e.g., the operational states of each fan 26 (i.e., on oroff), operational speed of each fan 26, etc. In one exemplaryembodiment, if the number of auxiliary fans 26 that are turn-on or thatare otherwise being operated simultaneously exceeds a set or otherwisedetermined threshold, then this potentially indicates that the building10 is experiencing a relatively widespread drop in the overall interiorair pressure (e.g., below the level which is generally desired), asopposed to simply an imbalance in the internal air pressure or alocalized variation. Accordingly, when this condition is detected by theAPCU 11 (e.g., from the monitored state of the auxiliary fans 26), theAPCU 11 optionally takes suitable remedial action. For example, togenerally raise or otherwise adjust the overall air pressure inside thebuilding 10, the APCU 11 optionally controls the main fan or set of mainfans 12 accordingly, e.g., turning-on the main fan or set of main fans12 and/or increasing its optional speed. As can be appreciated, theforegoing remedial action will generally tend to raise the overall airpressure inside the building 10. Moreover, such an increase in overallair pressure will generally also be detected in the various rooms/areas20 of the building 10, e.g., by the sensors 22. Accordingly, asdescribed above, the APCU 11 will in turn eventually turn-off one ormore of the auxiliary fans 26 when the air pressure in one or more ofthe rooms/areas 20 reaches or is otherwise restored to the desiredlevel, e.g., as a result of increasing the operational speed of the mainfan or set of main fans 12. Accordingly, once the number of auxiliaryfans 26 in simultaneous operation drops below the threshold, the APCU 11may optionally suspend the remedial action previously taken or at leastcease further progression of the remedial action—e.g., the operationalspeed of the main fan or set of main fans 12 may be maintained by theAPCU 11 at the level where the number of auxiliary fans 26 insimultaneous operation remains below the threshold.

Notwithstanding implementation of the foregoing remedial action, attimes the number of fans 26 in simultaneous operation may not drop belowthe threshold level as desired. For example, over time the filter 16 maybecome significantly clogged or otherwise compromised therebyrestricting airflow therethrough such that even when the main fan or setof main fans 12 has reached its maximum operational speed there is stillnot sufficient airflow through the filter 16 to generate or otherwiseachieve the desired air pressure inside the building 10, e.g., asmeasured or otherwise detected by the sensors 22. Accordingly, the APCU11 is optionally programmed or otherwise provisioned to sound an alarmor provide another visual or audible warning or other suitableindication of this condition. For example, after the APCU 11 has set theoperational speed of the main fan or set of main fans 12 to its maximumlevel or some other desired upper limit, the APCU 11 optionally sets aclock or other timer in motion. Meanwhile, the APCU 11 continues tomonitor the operational state of the auxiliary fans 26. If after theexpiration of a set or otherwise determined time period (e.g., measuredby the aforementioned clock or timer) the number of auxiliary fans 26 inoperation has still not fallen below the threshold level, then theremedial action (i.e., increasing the operational speed of the main fanor set of main fans 12) is optionally deemed to have failed, e.g., dueto a clogged filter 16. Accordingly, when this condition is met, theAPCU 11 optionally generates the aforementioned visual or audiblewarning or other suitable indication, e.g., which signals maintenancestaff or other suitable persons to check, clean, replace or otherwiseservice the filter 16. Suitably, during the foregoing maintenance, theAPCU 11 optionally operates and/or otherwise regulates the auxiliaryfans 26 so as to support the relative positive internal air pressure,e.g., while the main fan or set of main fans 12 may be turned off toperform and/or complete the maintenance. In this manner, the auxiliaryfans 26 can at least temporarily help prevent or hamper the entry ofexterior airborne contaminates or the like (i.e., by supporting thecreation of a relatively positive internal air pressure at theirrespective locations) and give the maintenance staff some time torespond to the alarm condition.

With reference now to FIG. 2, there is shown a process or method 100,e.g., implemented by the APCU 11 to regulate operation of the auxiliaryfans 26, that achieves a balanced internal air pressure, e.g., insidethe building 10. Suitably, the process or method 100 is implemented foreach pair of interior sensor 22 and auxiliary fan 26 arranged in thefacility or building 10. Optionally, the entire process or method 100 isiteratively repeated successively and/or continually to maintain abalanced air pressure inside the building 10 over time.

At step 102, the APCU 11 monitors the air pressure (AP) and/orvariations or changes therein over time. Suitably, the internal airpressure of a localized region within the building 10 is monitored,e.g., such as in a room or area 20, and optionally, the correspondingexterior air pressure is also monitored. In one suitable embodiment, airpressure measurements or other like readings are periodically,intermittently or otherwise obtained by the APCU 11 from the interiorsensor 22 and/or optionally from a corresponding exterior sensor (e.g.,such as exterior sensor 24).

At decision step 104, the APCU 11 compares the localized interior airpressure (LIAP) to a set or otherwise determined threshold (THLIAP).Suitably, THLIAP is set or otherwise determined to reflect the desiredinterior air pressure, e.g., which is optionally some positive amountrelative the monitored exterior air pressure, some absolute value, orotherwise. In the illustrated example, if the LIAP is less than thethreshold THLIAP, e.g., by more than a given tolerance, then the process100 branches to step 120. Alternately, if the LIAP exceeds the thresholdTHLIAP, e.g., by more than a given tolerance, then the process branchesto step 140. Otherwise, if the LIAP is substantially equal to thethreshold THLIAP, e.g., within a given tolerance, then the LIAP isacceptable and the current iterative cycle of the process 100 may end,while optionally maintaining the current operational state of theauxiliary fan 26.

At step 120, the APCU 11 sets the operational state of the auxiliary fan(AF) 26 to “on” and optionally provides the AF 26 a suitable signal orother message indicating the same. At decision step 122, the monitoredLIAP is again compared to the threshold THLIAP. If the LIAP remains lessthan the threshold THLIAP, e.g., by more than a given tolerance, thenthe process 100 continues to step 124, otherwise if the monitored LIAPnow meets or exceeds the threshold THLIAP, e.g., by more than a giventolerance, then the LIAP has been sufficiently corrected and the currentiterative cycle of the process 100 may end, while optionally maintainingthe current operational state of the AF 26.

At decision step 124, the APCU 11 checks the speed of the AF 26, e.g.,known from the monitored operational state of the AF 26. If the speed ofthe AF 26 is already at its maximum or at or above some other upperlimit, then the process 100 continues to step 126 where the APCU 11provides an audible or visual or other suitable warning or other likeindication of the current fault condition—namely, that the desired LIAPcannot be reached or maintained even at the maximum or upper limit ofthe AF's operational speed. Optionally, the APCU 11 may also takefurther automatic remedial actions, e.g., such as increasing the speedof the main fan or set of main fans 12. In any event, following step126, the current iterative cycle of the process 100 may suitably end,while optionally maintaining the current operational state of the AF 26.Alternately, at decision step 124, if the speed of the AF 26 is not atits maximum or is below some other upper limit, then the process 100branches to step 128 where the APCU 11 incrementally or otherwiseincreases the operational speed of the AF 26 and the process 100 loopsback and/or otherwise returns to step 122.

At decision step 140, the APCU 11 checks the operational state of the AF26. If the AF 26 is off, then the process 100 continues to step 142where the APCU 11 provides an audible or visual or other suitablewarning or other like indication of the current fault condition—namely,that excessive LIAP is being experienced even when the AF 26 is off.Optionally, the APCU 11 may also take further automatic remedialactions, e.g., such as decreasing the speed of the main fan or set ofmain fans 12. In any event, following step 142, the current iterativecycle of the process 100 may suitably end, while optionally maintainingthe current operational state of the AF 26. Alternately, at decisionstep 140, if the AF 26 is on, then the process 100 branches to step 144,where the APCU 11 checks the speed of the AF 26, e.g., known from themonitored operational state of the AF 26.

At decision step 144, if the speed of the AF 26 is already at itsminimum or at or below some other lower limit, then the process 100branches to step 146 where the APCU 11 sets the operational state of theauxiliary fan (AF) 26 to off and optionally provides the AF 26 asuitable signal or other message indicating the same. As shown,following step 146, the process 100 jumps to step 150 (i.e., bypassingstep 148). Alternately, at decision step 144, if the speed of the AF 26is above its minimum or some other lower limit, then the process 100continues to step 148 where the APCU 11 incrementally or otherwisedecreases the operational speed of the AF 26 and the process 100 thencontinues to step 150.

At decision step 150, the monitored LIAP is again compared to thethreshold THLIAP. If the monitored LIAP remains above the thresholdTHLIAP, e.g., by more than a given tolerance, then the process 100returns to step 140, otherwise if the monitored LIAP now meets or hasdropped below the threshold THLIAP, e.g., by more than a giventolerance, then the LIAP has been sufficiently corrected and the currentiterative cycle of the process 100 may end, while optionally maintainingthe current operational state of the AF 26.

With reference now to FIG. 3, there is shown a process or method 200,e.g., implemented by the APCU 11, to discriminate between generalizeddrops, losses or other changes in overall air pressure inside a facilitysuch as the building 10 and localized variations or imbalancesexperienced in the internal air pressure. Optionally, the entire processor method 200 is iteratively repeated successively and/or continually toguard against generalized losses or other unwanted changes in overallinternal air pressure, while still maintaining a balanced air pressureinside the building 10 over time. Suitably, iterative cycles of theprocess or method 200 may optionally be executed concurrently and/orconsecutively with each iterative execution cycle of the above-describedprocess or method 100.

At step 202, the APCU 11 monitors and/or records the current operationalstate of each of the AFs 26 arranged in the facility or building 10. Forexample, the APCU 11 monitors and/or records which AFs 26 are on and/oroff, the set or operational speed of each AF 26, etc.

At decision step 204, the number (N) of AFs 26 that are currentlyoperating (i.e., in the “on” state) is compared to a set or otherwisedetermined threshold (TH). As shown in the illustrated embodiment, if Nis not greater than or otherwise does not meet the threshold TH, then ageneralized drop or decrease in overall interior air pressure is deemedas not being experienced, and the current iterative cycle of the process200 may end, while optionally maintaining the current operational stateof the main fan (MF) or set of main fans 12. Otherwise, if N is greaterthan or does otherwise meet the threshold TH, then a generalized drop ordecrease in overall interior air pressure is deemed as beingexperienced, and the process 200 accordingly continues on to step 206for suitable remedial action.

At step 206, the operational state of the MF 12 is determined, e.g., bythe APCU 11. If the MF 12 is already on, then the process may advancedirectly to step 210, otherwise if the MF 12 is off, the processbranches to step 208 where the APCU 11 turns on the MF 12 beforeproceeding to step 210. At step 210, the operational speed of the MF 12is compared (e.g., by the APCU 11) to its maximum or other upper limit.If the maximum speed or other upper speed limit of the MF 12 has notbeen reached or met, then the process 200 advances to step 212 where theoperation speed of the MF 12 is incrementally or otherwise increased(e.g., by the APCU 11) and then the process 200 loops back and/orotherwise returns to step 204.

Alternately, at step 210, if the MF 12 has already reached or otherwisemet its maximum speed or other upper speed limit, then the process 200branches to step 214 where it is determined whether or not a timer orclock has been started or is currently running. Suitably, the timer orclock is programmed or otherwise provisioned (e.g., within the APCU 11)to count-down or otherwise measure or mark a set or otherwise determinedtime period. If the timer/clock has not been started or is not yetrunning, then the process 200 branches to step 216 where the timer/clockis started and the process then loops back and/or otherwise returns tostep 204. Otherwise, if the timer/clock has already been started, thenthe process 200 advances to step 218.

At decision step 218, the APCU 11 checks the timer/clock to determine ifthe set or otherwise determined time period has expired. If the set orotherwise determined time period has not expired, then the process 200loops back and/or otherwise returns to step 204, otherwise, if the setor otherwise determined time period has expired, then the filter 16 isdeemed to be clogged or otherwise compromised insomuch as the airflowproduced by the MF 12 operating at its upper or maximum speed limit forthe designated time period has still failed to produce the desiredeffect, i.e., a generalized increase in overall interior air pressuresufficient to decrease the number (N) of AFs 26 simultaneously beingoperated to a level below the determined threshold TH, and accordingly,the process 200 continues to step 220. At step 220, the APCU 11 providesan audible or visual or other suitable warning or other like indicationof the current fault condition. Optionally, the APCU 11 may also takefurther automatic remedial actions, e.g., such as operating orregulating one or more of the AFs 26 so as to support the relativepositive internal air pressure, e.g., while the main fan or set of mainfans 12 may be turned off to perform and/or complete maintenance on thefilter 16.

In one optional embodiment, the foregoing internal air pressure controlsystem is intended to be retrofit into an existing building.Accordingly, employing portable floor fans 26 and/or wirelesscommunication links between the APCU 11 and the sensors 22 and 24 andbetween the APCU 11 and the auxiliary fans 26 facilitates quick and easyinstallation of the system. However, in alternate embodiments, thesystem may be installed in conjunction with new construction orrenovation of a building or facility, in which case it may be moresuitable and/or desirable to employ hardwired communication linksbetween the various elements and/or more permanently installed auxiliaryfans 26. Additionally, while the foregoing description has been madewith reference to producing and/or maintaining a generally positiveinternal air pressure relative to the external air pressure, those ofordinary skill in the art will appreciate that the foregoing descriptionand/or above-described internal air pressure control system can bereadily adapted to maintain a relatively negative internal air pressureif it should so be desired.

In any event, it is to be appreciated that in connection with theparticular exemplary embodiments presented herein certain structuraland/or function features are described as being incorporated in definedelements and/or components. However, it is contemplated that thesefeatures may, to the same or similar benefit, also likewise beincorporated in other elements and/or components where appropriate. Itis also to be appreciated that different aspects of the exemplaryembodiments may be selectively employed as appropriate to achieve otheralternate embodiments suited for desired applications, the otheralternate embodiments thereby realizing the respective advantages of theaspects incorporated therein.

It is also to be appreciated that particular elements or componentsdescribed herein may have their functionality suitably implemented viahardware, software, firmware or a combination thereof. Additionally, itis to be appreciated that certain elements described herein asincorporated together may under suitable circumstances be stand-aloneelements or otherwise divided. Similarly, a plurality of particularfunctions described as being carried out by one particular element maybe carried out by a plurality of distinct elements acting independentlyto carry out individual functions, or certain individual functions maybe split-up and carried out by a plurality of distinct elements actingin concert. Alternately, some elements or components otherwise describedand/or shown herein as distinct from one another may be physically orfunctionally combined where appropriate.

In short, the present specification has been set forth with reference topreferred embodiments. Obviously, modifications and alterations willoccur to others upon reading and understanding the presentspecification. It is intended that the invention be construed asincluding all such modifications and alterations insofar as they comewithin the scope of the appended claims or the equivalents thereof.

1. In a building having a plurality of different localized areas, asystem for maintaining a balanced interior air pressure inside thebuilding, said system comprising: a main fan or set of main fans that isselectively controlled to support a desired overall interior airpressure inside the building; a plurality of interior sensors, eachinterior sensor arranged to detect a localized air pressure at one ofthe areas in the building; a plurality of auxiliary fans, each auxiliaryfan being provisioned to selectively modify the localized air pressureat one of the areas in the building; and, a control unit, said controlunit being in operative communication with the plurality of sensors toobtain air pressure readings therefrom, said control unit being inoperative communication with the plurality of auxiliary fans to controloperation thereof, and said control unit being in operativecommunication with the main fan or set of main fans to control operationthereof; wherein, based upon the localized air pressure detected by agiven sensor, a corresponding auxiliary fan, provisioned for the area inwhich the air pressure was detected by the given sensor, is controlledby the control unit to modify the localized air pressure at the area inthe building for which the corresponding auxiliary fan was provisioned.2. The system of claim 1, wherein the corresponding auxiliary fan isturned on by the control unit to boost the localized air pressure at thearea in the building for which the corresponding auxiliary fan wasprovisioned when the localized air pressure detected by the given sensorfails to satisfy a determined threshold.
 3. The system of claim 2,wherein the control unit monitors the number of auxiliary fans that aresimultaneously turned on, and when that number exceeds a determinedamount, then the control unit takes remedial action.
 4. The system ofclaim 3, wherein the remedial action includes increasing an operationalspeed of the main fan or set of main fans.
 5. The system of claim 3,said system further comprising: a warning signal, wherein if theremedial action does not result in the number of auxiliary fans that aresimultaneously turned on dropping to or below the determined amount,then the control unit activates the warning signal.
 6. The system ofclaim 2, said system further comprising: an exterior sensor arranged todetect an exterior air pressure at a location outside the building,wherein said control unit is in operative communication with theexterior sensor to obtain air pressure readings therefrom.
 7. The systemof claim 6, wherein the threshold is determine relative to the exteriorair pressure detected by the exterior sensor.
 8. The system of claim 7,wherein each of the interior sensors, the exterior sensor, the auxiliaryfans and the main fan or set of main fans are in operative communicationwith the control unit via at least one of a corresponding wireless orhardwired communication link.
 9. In a building having a plurality ofdifferent localized areas, a method for maintaining a balanced interiorair pressure inside the building, said method comprising: (a)selectively controlling a flow of exterior air into the building tosupport a desired overall interior air pressure inside the building; (b)detecting a localized interior air pressure in each of the localizedareas in the building, and, (c) selectively modifying the localizedinterior air pressure in a given localized area of the building inresponse to the detected localized interior air pressure at the givenlocalized area varying from the desired overall interior air pressure.10. The method of claim 9, said method further comprising: provisioningthe building with a plurality of auxiliary fans, each auxiliary fanbeing arranged to affect the localized interior air pressure of one ofthe localized areas, wherein the step of selectively modifying thelocalized interior air pressure is achieved by selectively controllingthe operation of the auxiliary fan provisioned in the building for thegiven localized area.
 11. The method of claim 10, said method furthercomprising: monitoring the number of auxiliary fans that aresimultaneously turned on; and, when the number exceeds a determinedamount, taking a remedial action.
 12. The method of claim 11, whereinthe remedial action includes increasing the flow of exterior air intothe building.
 13. The method of claim 12, said method furthercomprising: outputting a warning signal when the remedial action doesnot result in the number of auxiliary fans that are simultaneouslyturned on dropping to or below the determined amount.
 14. The method ofclaim 13, said method further comprising: detecting an exterior airpressure at a location outside the building.
 15. The method of claim 14,wherein the desired overall interior air pressure is determine relativeto the detected exterior air pressure.
 16. The method of claim 15, saidmethod further comprising: provisioning the building with a plurality ofinterior sensors, each interior sensor detecting the localized interiorair pressure at one of the localized areas in the building; and,providing at least one exterior sensor arranged to detect the exteriorair pressure.
 17. The method of claim 16, said method furthercomprising: providing at least one of a wireless communication link anda hardwired communication link over which each of the interior sensors,the exterior sensor and the auxiliary fans are in operativecommunication with a control unit provisioned to control the auxiliaryfans based on data received from the sensors.